Online court documents show Carl White pleaded guilty to third-degree murder and other charges in a deal with prosecutors on Tuesday, after the Philadelphia jury was selected for his trial.
White's lawyer, James Berardinelli, said White wanted to accept responsibility. He said White knows he'll be in prison for a long time and is "hoping to come out a changed man."
The elder Ellington was found shot in the head in the driver's seat of a car in northwest Philadelphia in November. His son was playing for the Los Angeles Lakers at the time.
Ellington Jr. said the sentencing provided closure for the family.
"It's bittersweet," he said at practice Wednesday in Brooklyn. "You always want justice to be served, but at the same time none of that could ever bring my father back."
White was arrested Dec. 4. Police said an argument might have sparked the shooting.
"(My father) meant a lot," Ellington said. "You only get one father, and the father-son relationship is a little bit different from any other relationship. I'm the only boy in my family, so it was a great bond we had, and I'm going to carry it on. He's going to live on through me."
Information from The Associated Press and ESPN's Mike Mazzeo was used in this report.